Tornado information and safety - KWWL - Eastern Iowa Breaking News, Weather, Closings

Tornado information and safety


Although tornadoes occur in many parts of the world, these destructive forces of nature are found most frequently in the United States. In an average year, 800 tornadoes are reported nationwide. On average, the state of Iowa sees about 49 tornadoes per year. Most of Iowa's tornadoes occur during the months of May and June. This is when the warm humid air from the Gulf of Mexico moves northwards and collides with the cool dry air from Canada. Most of Iowa's tornadoes occur during the late afternoon hour through the late evening hours. That's because in order for severe weather and tornadoes to develop, the atmosphere needs to become unstable. This usually happens with the heating of the day.

The Enhanced Fujita Scale (EF Scale) rates the strength of a tornado based on the damage it causes. By looking at the damage left behind, meteorologists can estimate the wind speeds inside a tornado. Most tornadoes in Iowa are rated either an EF0 or an EF1. A tornado that is rated an EF0 has estimated wind speeds of 65-85 mph. It usually leaves behind light damage such as broken tree branches or damaged chimneys. An EF1 tornado has estimated wind speeds of 86-110 mph and leaves behind moderate damage. This may include broken windows, snapped trees, and damage to roofs and garages. If you are interested in learning more about the other EF ratings, check out our website

When a tornado warning is issued for your area, seek shelter immediately. We recommend going to the lowest point of your house, preferably the basement. Try to take shelter in an inner hallway or a small interior room without windows, such as a closet or bathroom. Put a blanket or something over you to protect you from flying debris. Most tornado injuries come from flying debris.

If you don't have a basement, look for an interior room such as a closet or bathroom. Put as many walls between you and the tornado. If in a bathroom, get into the shower or bathtub for added protection. Always stay away from windows! Windows can easily break during a tornado allowing debris to enter your home.

If you are in a mobile home or other portable structure, leave the structure immediately. Tornado winds can easily pick up and toss these structures even if they are equipped with tie-downs. (Image of damaged mobile home) Take shelter in a building with a strong foundation. Most mobile home parks have a designated tornado shelter. As a last resort, take cover in a ditch or low-lying area a safe distance from the mobile home. Lie face down and cover your head and neck with your hands.

If you are in a vehicle, seek shelter immediately. Do not try to outrun a tornado. Tornadoes can change direction quickly and can easily lift a vehicle into the air. Get out of the vehicle and try to take shelter in a nearby home or building. Do not seek shelter under a highway overpass. Highway overpasses make terrible tornado shelters because they are above ground level. Tornado winds are stronger just above ground level and winds actually increase as they get funneled through the overpass. Plus, highway overpasses leave you vulnerable to flying debris. As a last resort, take cover in a ditch or low-lying area a safe distance from your car. Lie face down and cover your head and neck with your hands.

Some tornadoes are clearly visible, while rain or nearby low-hanging clouds obscure others. Occasionally, tornadoes develop so rapidly that little, if any, advance warning is possible. Before a tornado hits, the wind may die down and the air may become very still. A cloud of debris can mark the location of a tornado even if a funnel is not visible. Listen for a continuous roar or rumble, similar to a freight train; this often marks the approach of a tornado. Also, strong winds in a tornado will snap power lines, so look for bright flashes of light near the ground. Tornadoes generally occur near the trailing edge of a thunderstorm, usually after the rain and hail. It is not uncommon to see clear, sunlit skies behind a tornado.

There is no such thing as guaranteed safety inside a tornado. Freak accidents happen; and the most violent tornadoes can level and blow away almost any structure. Weather forecasting science is not perfect and some tornadoes do occur without a tornado warning. There is no substitute for staying alert to the sky. After you have received a warning or observed threatening skies, YOU must make the decision to seek shelter before the storm arrives. It could be the most important decision you will ever make.

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